It is known to drop incendiaries from aircraft such as helicopters and light fixed wing aircraft for the purposes of forestry management and back burning. One known incendiary is in the form of a small sphere (of approximately 32 mm diameter) of plastics material filled with a quantity of potassium permanganate granules or powder. The sphere is injection moulded from extruded plastic. A small hole is formed in the sphere to allow filling with a volume of potassium permanganate. The hole is then sealed with wax or glue. These spheres are typically dropped from dispensers mounted in aircraft. The dispensers are provided with a hopper for holding a large number of spheres and feeding the spheres sequentially to a chute where they are injected with a small volume of glycol. The potassium permanganate and glycol react exothermically leading to the generation of a flame.
Ideally, the flame is produced about 20-30 seconds after injection of the glycol by which time the spheres have been ejected from the dispenser and reached the ground.
While this form incendiary has performed adequately, it does suffer from several problems. Because of their shape the spherical incendiaries are inherently difficult to store and, if they spill from the hopper roll to various parts of the aircraft leading to potential safety hazards. Further, the spheres have a surprisingly low reliability in the order of 80%. This is in part due to difficulties in sequentially feeding the spheres to a chute and then successfully injecting them with glycol. It is not uncommon for the spheres to become jammed in the chute which then requires manual clearing. If the clearing is not performed expeditiously, there is a risk of combustion occurring within the chute itself. Consequently it is a requirement that this type of incendiary be attended to on a full time basis during dispensing. Another reason for their relatively low reliability is that if a sphere is orientated so that the needle injecting the glycol is aligned with the previously described wax or glue seal, the needle can become blocked preventing the injection of glycol and thus halting the operation of the dispenser. To recommence the injecting and dispensing process the blocked needle has to be removed, cleaned and reinstalled.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.